Is there anyone out there who can tell me which brake pads are required on my road bike? I have a Trek Pilot 2.1. The brakes are not labeled as Shimano, but the drive train is Shimano 105. Rims are Bontrager SSR alu. I put a tape measure up to the brake shoe and it appears to be about 52mm. Short of taking the existing pad out and then to a shop, is there any other way?